|  | 2.2 |
Full-Duplex Transmitting, Fast Ethernet Standard and LAN Segmentation
| 2.2.5 |
Pros and cons of LAN segmentation with switches
LAN switching eases bandwidth shortages and network bottlenecks, such as those between several PCs and a remote file server. A switch can segment a LAN into microsegments, which are single host segments. This creates collision-free domains from one larger collision domain. Although the LAN switch eliminates collision domains, all hosts connected to the switch are still in the same broadcast domain. Therefore, all nodes connected through the LAN switch can see a broadcast from just one node. Switched Ethernet is based on Ethernet. Each node is directly connected to one of its ports or a segment that is connected to one of the switch's ports. This creates a 10-Mbps bandwidth connection between each node and each segment on the switch. A computer connected directly to an Ethernet switch is its own collision domain and accesses the full 10 Mbps. A LAN that uses a Switched Ethernet topology creates a network that behaves as though it has only two nodes-the sending node and the receiving node. These two nodes share the 10-Mbps bandwidth between them, which means that nearly all the bandwidth is available for the transmission of data. Because a Switched Ethernet LAN uses bandwidth so efficiently, it can provide more throughput than Ethernet LANs connected by bridges or hubs. In a Switched Ethernet implementation, the available bandwidth can reach close to 100%. Ethernet switching increases the bandwidth available on a network by creating dedicated network segments (that is, point-to-point connections) and connecting those segments in a virtual network within the switch. This virtual network circuit exists only when two nodes need to communicate. This is why it is called a virtual circuit, it exists only when needed and is established within the switch. One drawback of switches is that they cost more than hubs. However, many businesses implement switch technology slowly by connecting hubs to switches to such a time that the hubs can be replaced.
| Web Links
| LAN Switching
| Migration to Switched Ethernet LANs